More than 500 members of the Public Service Association stopped work for two hours at the Ministry of Education on Thursday over a lack of progress in pay talks.
The PSA says its members want a pay system with progressive salary steps rather than discretionary increases.
The union says other ministry employees who are covered by the Educational Institute have such a system.
It says its members had their pay frozen last year while some mangers received bonuses.
PSA national secretary Brenda Pilott says the talks have been going for a year.
She says they have discussed a pay rise similar to the 1.5% achieved by other public servants this year.
